1. Field of the Invention
The present invention relates to a method for applying photo resists to an otherwise incompatible substrate.
2. Description of the Prior Art
The technique of applying images to substrates through the use of a photo resists has long been known and many uses therefor currently exist, particularly in preparing printed circuits in a manner described in U.S. Pat. No. 3,547,629, for example, or in making highly sophisticated scientific apparatus such as described in U.S. Pat. No. 3,808,001, for example. These resists are also used in the preparation of various articles where an image is desired such as, for example, edge-lighted panels such as are used as aircraft instrument panels.
In certain applications, such as, for example, space craft where there is a concern about flamability and outgassing it is necessary to use baked enamel paints for such panels. However, etching such panels to display images containing needed information has been found to be difficult since the photo resist material will not adhere adequately to the baking enamel substrate to allow a proper image to be formed. While photo sensitive resist materials will adhere to a partially cured lacquer surface the lacquer will discolor when an uncured enamel is cured at elevated temperatures. I have now discovered a method for applying photo resist materials to substrates which are normally incompatible with the photo resist material, particularly substrates painted with a baking enamel substrate.